A home NodeB is a small and low-power base station and deployed at indoor places such as homes and offices, and mainly aims at providing a higher service rate and lower fees required by high rate services for the users, and also makes up for the shortcomings in coverage of existing distributed cellular wireless communication systems. The home NodeB has advantages of benefits, convenience, low power output, plug and play, and etc.
The home NodeB accesses a core network via a logical network element, i.e. a home NodeB gateway, and as shown in FIG. 1, the home NodeB gateway mainly executes the following functions: verifying the security of the home NodeB, processing the registration of the home NodeB, performing working maintenance and management on the home NodeB, configuring and controlling the home NodeB according to the requirements of operators, and being in charge of exchanging data between the core network and the home NodeB. A user of the home NodeB needs to conduct relevant registration at the home NodeB gateway before using the home NodeB, and makes the gateway store context information of the user through a user registration flow, so that the home NodeB gateway performs management operations on the signaling message of the user. The registration process of a user of the home NodeB is shown in FIG. 2, specifically comprising the steps as follows.
S201, a user needs to establish an RRC (Radio Resource Control) connection as a bearer of the signaling message or service data before conducting communication.
S202, the user triggers the registration process through initializing an NAS (Non Access Stratum) message, and the message type can be an attachment message, a location/Routing area update message, a service request message and etc.
S203, the home NodeB does not find any context identifier information of the user and then sends a registration request message to the home NodeB gateway to register user information at the home NodeB gateway, and the contents of the message comprise information such as the type of the registration, the IMSI (International Mobile Subscriber Identify) identifier of the user, a home NodeB identifier, and etc.
S204, the home NodeB gateway verifies the ability of the user which accesses the home NodeB, if it allows the user to use resources provided by the home NodeB, accepts the registration, establishes a user context, and carries user context identifier information in a registration response message replied to the home NodeB.
S205, the home NodeB gateway transparently forwards an NAS message sent from the user to the core network without performing any processing on the message.
S206, the core network performs starting authentication and a security flow to verify the user according to the received NAS message.
S207, if the user passes the authentication and security verification, and the core network side performs corresponding specific operations according to the NAS message sent from the user, the core network side replies an NAS response message to the user to bring the information of the core network side to the user, this message is transparently transmitted between the user and the core network without being performed with any processing by the home NodeB and the home NodeB gateway.
It can be concluded from the above description that the prior art must perform user registration process to make the home NodeB and the home NodeB gateway obtain a user context identifier, and the home NodeB and the home NodeB gateway use this identifier to distinguish that a signaling transmitted at an RUA (RANAP User Adaptation) protocol layer belongs to RANAP (Radio Access Network Application Part) message of which user, and provide adaptation between an RANAP and an SCTP (Stream Control Transmission Protocol). However, when the user performs cell handover and the target cell is a home NodeB, as the user has never initiated any initialization NAS message in this cell, the target home NodeB and the target home NodeB gateway will not have the context identifier information of the user. Then a signaling message cannot be corresponded, and the handover procedure cannot be completed normally.
Currently no effective solutions have been put forward for the problem in the prior art that the handover procedure cannot be completed normally if a target cell is a home NodeB when a user performs cell handover.